Document WO-A-97/10117 describes an example of a vehicle seat of the above-mentioned type.
The seat presented in that document nevertheless suffers from the drawback that when the upper portion of the seat-back reaches its second angular position, the pivoting of said upper portion is stopped suddenly, thereby running the risk of subjecting the seat passenger to an impact.
In an attempt to mitigate that drawback, the above-mentioned document provides that after the upper portion of the seat-back has pivoted forwards, the seat-back as a whole pivots rearwards while being retained by a spring. However that disposition further complicates implementation of the seat and, in addition, rearward pivoting of the entire seat-back runs the risk of injuring passengers situated behind the seat-back, or even of injuring the user of the seat if hard and bulky objects happen to be located behind the seat-back.